Attachment plug



g g J. C SAMPSON ATTACHMENT PLUG Filed Sept. '7, 1928 Patented Mar. 24, 1931 UNITED 'STATES PATENT OFFICE JOHN C. SAMPSON, OF ST. LOUIS, MISSOURI, ASSIGNOB OF ONE-HALF TO iTULIAN IE. SAMPSON, OF UNIVERSITY CITY, MISSOURI ATTACHMENT PLUG Application filed September 7, 1928.

This inventionpertains to electric attachment plugs, such as are used at the end of a flexible cord for the purpose of connecting an electrical appliance to the supply circuit.

One of the objects of this invention is to provide an attachment plug having incorporated therein a fuse member by which the appliance served thereby may be provided with a removable and renewable fuse member, which may be assembled therewith and which may be easily renewed when a fuse has been blown.

Another object is to provide such a plug with an arrangement of contacts, such that it is impossible to assemble the device in the wrong manner.

Another object is to provide such a plug so arranged that it is impossible to use the plug in the normal manner without a proper fuse mounted thereon.

Another object is to provide such a plug with a fuse-holding member so arranged that the fuse therein may be easily replaced when blown.

Another object is to provide such a plug with an assembled fuse member so arranged that the fuse member is held in assembled relation rigidly enough so that it will not be separated by the operation of removing the plug from its socket or receptacle.

Further objects will appear from the following description, taken in connection with the accompanying drawing, in which- Figure 1 is a side view of an attachment plug embodying this invention;

Figure 2 is a longitudinal section, taken on line 22 of Figure 1;

Figure 3 is a side View of the base portion only;

Figure 4 tion;

Figure 5 is a transverse section, taken on line 5-5 of Figure 2; and

Figure 6 is a perspective detail of the fuse assembly.

Referring to the drawing, 1 designates a base portion, which may be constructed of molded insulation or any other suitable material, and is rovided with a central assage 2 through WhlCh the flexible cord or ot er cir-' is a similar view of the body por- Serial No. 304,407.

cuit conductor may beled to the interior parts. Mounted in the base 1 is an elongated contact blade 3, which may be provided with recesses 4 adapted to engage a suitable sprin catch in the receptacle or socket into whic the blade may be inserted. The contact blade 3 is of ordinary construction, such as is used in attachment plugs of the push ty e, except that it is considerably elongated f dr a purpose which will presently be pointed out. This contact may be attached to the base 1 by means of one or more rivets 5, or other suitable fastenings. The base 1 is also provided with an additional contact blade 6 set opposite the blade 3 in the usual manner and also secured by rivets 5 or similar fastenings. In accordance with the present invention, however, the blade 6 has its end formed with a curl 7 as shown more clearly in Figure 3, and is set in an angular position with respect to the contact 3. In the arrangement shown in a the drawing, the blade 6 is set at right angles to the blade 3. The former blade is also considerably shorter than the latter.

A body portion 8, also of molded insulation or similar material, provides a fuse member on whichthe fuse is mounted. This body member is constructed with an annular flange 9and has its body portion cut away, as shown in Figure 5, to accommodate contact elements 10 an 11. The contact element 10 comprises a fiat plate secured in place on the body 8 by a screw 12 or other suitable fastening, and has its end portions bent upwardly, as shown at 13 (Figure 2). These upwardly bent portions provide a clip or socket adapted to receive the curled end 7 of the contact 6 when the base and the body are assembled together, as illustrated in Figure 2. The clip portions 13 are provided with struck up knobsor lugs 14 adapted to engage in the open ends of the curled part 7 ,so as to hold the contact 6 securely in their grip when the parts are assembled as in Figure 2. The contact element 11 ma have the form of a screw or similar fastening, which serves a double purpose of holding a contact blade 15 in place on the body 8 and also providing a terminal for the fuse strip 16. The fuse 16 passes from the terminal 11 around the circular portion of the body 8 and its other end is attached by soldering or otherwise to the contact 10. The body 8. is

provided with a cover or cap 17 having a' flange 18 surrounding the circular part of the body portion 8 and enclosing the fuse 16. The flange 18 may be provided at one side with a window 19 opposite the reduced por- 7 tion 20 of the fuse 16, in order that an observer may tell, by looking through the window 19, whether or not the fuse is intact. A strip of mica 21 or similar material may be placed within the flange 18 so as to protect the fuse through both of them, adapted to receive the blade 3 when in assembled relation. This blade passes clear through the body and prof jects from the opposite side in a position parallel to the blade. 15.

These two blades are proportioned to fit a standard push plug rcceptacle. The cap 17 may be secured in place by a screw 23 or similar fastener.

\Vhen this plug is in use, the flexible cord or other circuit conductors are led through the passage 2 and connected to the contacts 3 and 6 in the usual manner. When this has been done, the body 8, assembled with its fuse, is applied to the base 1 by slipping the blade 3 through the opening 22 and engaging the blade 6 in the socket 13. This not only places the parts in assembled relation and secures them so, but also establishes the necessary electrlcal circuit connections.

The blade 3 passes clear through the body, while the blade 6 contacts with the clip 13 at one end of the fuse 16, whose other end is connected to the blade 15. When thus assembled, the dev1ce may be used as an ordinary push plug in 1any standard socket or receptacle of the same It will be noted that this invention provides a number of advantageous features. The body portion provides a renewable fuse member, which may be detached from the base 1 when the fuse has been blown and a new one applied. It is also convenient to renew thefuse 16 by simply removing the cap 17 and replacing the strip of fuse material with a new strip. When the body portion has been removed, the remaining portion is not usable as a push plug; since, in the first place, the blade 3 is much longer than the blade 6 and would prevent establishing circuit connections; and, in the second place, the blade 6 is placed at right angles to the blade 3 and provided with an enlarged curl 7 so that it would not enter astandard socket. This arrangement, renders it impossible to insert the base portion by itself into a standard socket and use the device without fuse protection. The fuse may be removed by simply applying anew bod portion complete. This portiends Sim e and cheap to can, therefore, be supplied at a very slight cost. If made of glass or similar material, the condltlon of the fuse can be easily seen at any time.

The arrangement of the clips 13 with short arms and the projections 14 adapted to engage the curl 7 of the contact-6, provides that, when the parts are in assembled relation, the base and the body are held together firmly so as to require more force for their separation than is required to pull the blades 3 and 15 out of their sockets. Accordingly, if the user should attempt to remove the plug from its socket by simply pulling on the cord, as is frequently done, the blades 3 and 15 would be released from their sockets before the blade 6 could be pulled out of the socket 13. This provides for keeping the assembly of the base 1 and the body 8 mtact until it is necessary to renew a fuse. In the latter case, little additional force Wlll separate the base and the body.

This constriu-tion also makes it a s mple matter to connect this plug to the circuit conductors. By simply removing the body portion. the terminals of the contacts 3 and 6 are exposed so that connections may be made in the usual manner. g

It will be seen that, while the assembled unit provides a plug, having contact blades projecting therefrom 1n the usual manner and arranged to fit a standard socket, the separation of the body from the base renders the device unfit for use until a new fuse or a new fuse member has been assembled in its stead.

This plug will, therefore, serve as complete protection for the appl ance to whlch it is connected, to guard against the use of the same without a proper fuse in the circult.

While the device has been described as a unitary plug, it will be understood, of course, that sub-combinations thereof may be found useful by themselves, and the use ofsuch sub-combinations is contemplated by this 111- vention. It is further obvious that varlous changes may be made, within the scope of the appended claims, in the details of construction without departing from the spirlt of this invention; it is, therefore, to be understood that this invention is not limlted to the specific details shown and described.

Having thus described the invention, what is claimed is:

1. An electric attachment plug, compris-' blade and permanently mounted on said body. a

2. An electric attachment plug, comprising, a base portion, a body portion adapted for assembly therewith, a pair of contact blades rojecting from said body, one of said said body and connected to the other end of blades eing mounted on said base and exsaid fuse.

tending through said body, and a fuse perma- In testimony whereof I aflix my signature nently on said body interposed in the circuit this 9th day of April, 1928.

' of one of said blades. JOHN C.-SAMPSON.

3. An electric attachment plug, comprising, a base portion, a body portion adapted for assembly therewith, said body having a fuse permanently'mounted thereon and pro- 10 viding a renewable fuse member, a pair of contact blades projecting from said body, one of which is mounted on said base, and means gompleting the electric circuit through said use. 15 4. An electric attachment plug, comprising, a base portion having a pair of contact blades adapted for connection to a circuit conductor, a body portion adapted for assembly with said base portion and provided 20 with a passage therethrough for one of said blades and a contact socket adapted to receive the second blade, a third contact blade on said body portion, and a fuse on said body portion connecting said socket with said third 25 blade.

I 5.,An electric attachment plug, comprising, a base portion, a body portion adapted for assembly therewith, said body having a fuse thereon and providing a renewable fuse a member, a pair of contact blades projecting from said body, a plug socket adapted to receive and hold said blades, and means including a spring clip adapted to hold said base i and said body in assembled relation with a 5 force greater than that required to pull said blades from said socket. 1

6. An electric attachment plug, comprising, a base portion, a body portion adapted for assembly therewith, said body having a 4o fuse thereon and providing a renewable fuse member, a pair of contact blades projecting from said body, one of said blades being mounted on said base and the second on said body, and a third blade on said base adapted 45 to engage a socket on said body to hold said parts in assembled relation.

7. An electric attachment plug, comprising, a base portion, a body portion adapted for assembly therewith, a contact' blade on l0 said base projecting thru said body, a second I contact blade on said base, a clip on said body engageable with said second contact, a third contact blade projecting from said body, and a fuse mounted on said body and 55 connectin said third contact with said clip.

8. An, e ectric, attachment plug, com rising, a base ortion having a long'and a s ort contact bla e thereon ada ted for connection to circuit conductors, a y portion adapted no for assembly with said base having a fuse mounted therein and provided with a passage therethru for said lon contact blade, a clip on said body enga ab e with said short contact and'connec, foone end of said and wardcontact blade projecting from 

